2049 - NFS

Theory

NFS is a system designed for client/server that enables users to seamlessly access files over a network as though these files were located within a local directory.

A notable aspect of this protocol is its lack of built-in authentication or authorization mechanisms. Instead, authorization relies on file system information, with the server tasked with accurately translating client-provided user information into the file system's required authorization format, primarily following UNIX syntax.

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Practical

Enumeration

Nmap Scripts

nfs-ls #List NFS exports and check permissions
nfs-showmount #Like showmount -e
nfs-statfs #Disk statistics and info from NFS share

Metasploit Modules

scanner/nfs/nfsmount #Scan NFS mounts and list permissions

Mounting a Share

showmount -e <IP>

mkdir /mnt/new_back
mount -t nfs [-o vers=2] 10.12.0.150:/backup /mnt/new_back -o nolock

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REFERENCES

• https://book.hacktricks.xyz/network-services-pentesting/nfs-service-pentesting

• https://medium.com/@karan_shergill/network-file-system-nfs-enumeration-exploitation-14c154a4d2c1

• https://library.mosse-institute.com/articles/2022/07/nfs-enumeration-for-low-privilege-access/nfs-enumeration-for-low-privilege-access.html